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A thermotolerant acetic acid bacterium, designated strain CWBI-B418T, isolated in Senegal from mango fruit (Mangifera indica), was characterized in detail by means of genotypic and phenotypic methods. The novel strain was strictly aerobic and exhibited optimal growth on YGM medium at 35 °C. Cells were Gram-negative, motile and coccoid. The strain was assigned to the genus Acetobacter on the basis of 16S rRNA gene sequence analysis. DNA–DNA hybridization experiments with its phylogenetically closest relatives showed that strain CWBI-B418T represented a novel Acetobacter genospecies. The DNA G+C content of strain CWBI-B418T was 56.0 mol%. Phenotypic characteristics enabling the differentiation of strain CWBI-B418T from phylogenetically related Acetobacter species were: production of 2-keto-d-gluconic acid from d-glucose, but not 5-keto-d-gluconic acid, production of catalase but not oxidase, growth on yeast extract with 30 % d-glucose, growth with ammonium as sole nitrogen source with ethanol as carbon source, utilization of glycerol and ethanol but not maltose or methanol as carbon sources, and growth in the presence of 10 % ethanol. Based on the genotypic and phenotypic data presented, strain CWBI-B418T clearly represents a novel Acetobacter species, for which the name Acetobacter senegalensis sp. nov. is proposed. The type strain is CWBI-B418T (=LMG 23690T=DSM 18889T).

Lactococcus lactis subsp. lactis strain CWBI B1410, which produces various antibacterial compounds including organic acids and nisin, was used as a starter culture to improve the traditional Senegalese fish fermentation in which fish are mostly transformed to guedj by spontaneous fermentation for 24 to 48 h at ambient temperatures near 30 degrees C followed by salting (with NaCl) and sun drying. Assays were performed on lean fish (Podamasys jubelini) and fat fish (Arius heudelotii) purchased at a local market. The total viable microbial counts in raw fillets of P. jubelini and A. heudelotii were 5.78 and 5.39 log CFU/g, respectively. Populations of enteric bacteria (which can include pathogenic bacteria) in P. jubelini and A. heudelotii were 4.08 and 4.12 log CFU/g, respectively. Spontaneous fermentation of raw fillets at 30 degrees C led to the proliferation of enteric bacteria to 9 log CFU/g after 24 h in fermented P. jubelini and A. heudelotii fillets with pH values of 6.83 and 7.50, respectively. When raw fish fillets were supplemented with glucose (1%, wt/wt) and inoculated with Lactococcus lactis (10(7) CFU/g), the pH decreased to about 4.60 after 10 h at 30 degrees C, and nisin activity was detected in juice from the fillets. Traditionally fermented fillets of P. jubelini and A. heudelotii contained enteric bacteria at higher levels of 4 and 2 log CFU/g, respectively, than did fillets of the same fish supplemented with glucose and fermented with the starter culture. These data suggest that this new fish fermentation strategy combined with salting and drying can be used to enhance the safety of guedj.

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The protective effects of the fatty acid composition and membrane action of the acidification activity of two strains of Lactobacillus kept at 20°C were studied. The addition of sorbitol, monosodium glutamate and glycerol during storage is causing the decline of acidification and increased concentrations of unsaturated fatty acids observed in both strains. The addition of sorbitol and monosodium glutamate does not alter the fatty acid composition, whatever the strain, but increases the resistance to freeze-drying of L. plantarum CWBI-B1419 and improves survival during storage. The addition of these preservatives and decreased activity of acidification improves the ratio unsaturated. These results indicate that the survival during storage and freeze-drying resistance are closely related to the composition of membrane fatty acids. This behaviour can be interpreted as an adaptation of L. plantarum B1419-CWBI supplemented by cryoprotectant additives such as sorbitol or monosodium glutamate sorbitol and monosodium glutamate as an additive. L. plantarum CWBI-B1419 presents a greater adaptation to culture conditions than L. paracasei ssp. paracasei LMG9192T.